Introduction to Transient Simulations GasTurb 13 Introduction to Transient Simulations Copyright © GasTurb GmbH

For this tutorial we will use a 2 Spool Turboshaft GasTurb 13 Main Window For this tutorial we will use a 2 Spool Turboshaft Copyright © GasTurb GmbH

Select the engine model We Need Some Data Select the engine model Open the engine model Copyright © GasTurb GmbH

Off-Design Input Data Page Run the Off-Design cycle Copyright © GasTurb GmbH Run a Single Cycle with HPC Spool Speed ZXN = 0.8. The transient simulation will begin at this operating point.

Off-Design Point Summary Close the result window Copyright © GasTurb GmbH At this operating point the shaft power is 308.5kW while at the cycle reference point 934.9 kW are delivered.

Initialize Transient Simulations Click here to initialize transient simulations Select “Initialize Transient” Copyright © GasTurb GmbH Before beginning with transient simulations, a steady state operating line needs to be calculated. These steady state data will be shown together with the transient simulation results for comparison.

Operating Line in the Compressor Map Close the window Copyright © GasTurb GmbH Before closing this window you can look at all the correlations you are interested in.

Off-Design Input Window Switch to Transient Simulations Click here to run a transient simulation Select “Transient” Select “Transient” to see the transient input window Copyright © GasTurb GmbH

Setup a Pilots Lever Schedule Click here to start the transient simulation The schedule can be modified by selecting “Move Point” and “Delete Point” Select “Add Point” And click on the marked positions Copyright © GasTurb GmbH Setup an example Pilots Lever schedule

Transient Output Overview Select “Compr” For viewing other results click the y=f(x). To see the compressor operating line click the Compr tab. Burner exit temperature Gas generator spool speed Power turbine spool speed Copyright © GasTurb GmbH

Compressor Map Copyright © GasTurb GmbH Close the window Transient operating line Steady state operating line Copyright © GasTurb GmbH To begin with a new transient maneuver, close this window, then click Run in the Off-Design Input Window.

Simulations with Disabled Control System In the previous simulations with Pilots Lever=f(Time) input a simple PID controller was active. If Gas Generator Speed or Fuel Flow is given as function of time then the control system is disabled. Click on Formulas If you want to make any input quantity a function of time which is not offered in the Time Schedule Input then use a combination of composed values with iteration. Copyright © GasTurb GmbH

Making any Input Quantity a Function of Time Click on Tables Copyright © GasTurb GmbH First, we have to define a table, containing the schedule of our input quantity

Making any Input Quantity a Function of Time Enter a name for the table here (optional) Close the window Choose time as X-Value and enter numbers for the quantity of interest in the Result row. At time=0 the number must be the same as for the steady state condition at which the transient maneuver begins. Copyright © GasTurb GmbH

Calling a Table as Composed Value Close the window Copyright © GasTurb GmbH The table will show on the Tables page in the composed values editor. Insert the table as a formula, then close the window

Define an Iteration… Click on Iteration Copyright © GasTurb GmbH

Define an Iteration… Copyright © GasTurb GmbH Do not forget to activate the iteration, then close the window Close the window Choose Delta T from ISA as iteration Variable… …the composed value as iteration Target …and enter the = sign for the target value Copyright © GasTurb GmbH

Run the Simulation… Copyright © GasTurb GmbH Now you can run any of the transient simulations. In the following example we use the Fuel Step option. In this option the fuel flow is increased after one second by 10% and remains constant at the new level. Select Fuel Step Copyright © GasTurb GmbH

Transient Simulation Tutorial Run the Simulation… In the time span from 5 to 6 seconds the ambient temperature is 20° higher. That yields with constant fuel flow an increase in spool speed and T4. Copyright © GasTurb GmbH This slide ends the Transient Simulation Tutorial